Vascular stents are commonly used to restore patency to a myriad of vessels. These stents are often deployed with a drug applied to the surface, either directly, or with a polymer. It is desirable to increase the volume of drug carried upon the stent, and previous solutions have provided for the depots, channels, pores, or similar surface modifications in an exterior surface of the stent. Typically, these modifications result from the application of a mechanical or chemical force to the surface of the stent. For example, some surface modifications are stamped onto the surface, while other stents receive a chemical bath to etch a pattern, such as with lithography.
Another prior solution includes attaching a layer of an alloyed material to a base stent, and then applying a dealloying process to the layer. As the alloyed material is dealloyed, a portion of the alloy leaches out of the material, leaving a plurality of micropores in the layer. However, this technique requires that the layer of alloyed material be joined to a base stent, and further results in formation of the desired pores solely within the alloyed layer.
It would be desirable, therefore, to overcome the limitations of the prior art.